This invention is related generally to a modular document scanning system and particularly to a modular scanner supporting both sheet fed and platen scanning of documents. More particularly, the invention relates to a modular scanning system with a detachable platen element for single sheet scanning.
Document scanners have become a popular computing accessory both in the home and the office. Essentially, document scanners (or simply xe2x80x9cscannersxe2x80x9d) come in three distinct varieties: sheet fed scanners, platen scanners and combination sheet fed with platen capability scanners. With respect to sheet fed scanners, an image forming subsystem, such as a camera, typically a CCD or xe2x80x9ccharge couple devicexe2x80x9d and a lens in combination with an illumination source, scans an image by moving a sheet of paper past the camera, which sits in a stationary position. Individual raster lines are imaged by the camera and then pieced together to create a 2D image representation of the original document. With sheet fed scanners, the camera is basically looking at one sliver of the document many times as the document is moved across a lens. The paper motion supplies one dimension of the document while the width is supplied by the camera. The in-paper travel direction and the width of the document is determined by the optics magnification and the charged couple device (CCD) within the image forming subsystem.
In some cases, the shape of the sheet fed scanners paper path is semi-circular. For example, some scanners have a semi-circular paper path where sheets can be fed from a tray on top and exit beneath (or vice versa). In other cases, the paper path is xe2x80x9cstraight through.xe2x80x9d
With a platen scanner, a document is placed face down onto a stationary flat, usually glass surface, of the scanning unit and the image forming subsystem (camera and illumination source) moves underneath the fixed document to perform the scanning operation. In this case, the camera""s motion is providing the length while the camera""s optics provides the width of the scanned document.
Production scanners vary in speed, function and cost and are often used by businesses for scanning large quantities of documents. For example, scans of several hundred (100) to several hundred thousand (100,000) pages per job are typical for xe2x80x9cproductionxe2x80x9d scanners. One type of production scanner attempts to combine the functionality of a sheet fed scanner with that of a platen scanner. Essentially, with such combination production scanners, multiple sheets are fed from a stack past a stationary camera, thus eliminating the need for lifting a lid and placing document sheets face down one at a time. The platen capability is also employed to deal with documents that do not feed from a stack reliably. Production scanners of this type are manufactured as a single unit that combine the platen scanning functions with the sheet moving functions in a single box.
In one common configuration, a dual camera image forming subsystem is used with a paper path extending between the cameras and the scanner adapted to operate in two distinct scanning modes. In a sheet fed or straight-through scanning mode, documents are fed from a stack in between the cameras so that they are imaged on both the top and bottom during the same scanning operation. In a platen scanning mode, one of the cameras can be made to mimic the functionality of a platen scanner by placing a platen element adjacent to it and moving the camera beneath a stationary document placed on the platen. In this way, a stationary camera assumes the role of a platen image forming subsystem. Such combination production scanners are often known as platen scanners with autofeed capability. Essentially, this class of scanning devices utilizes a small paper path in combination with a camera that can operate in both a parked position for the auto-feed with subsequent movement of a document for sheet fed scanning as well as a moving operation for a stationary document during platen scanning.
With prior sheet fed, platen, or combination scanners, the user must select one type in favor of another. For those customers whose primary need is for a sheet fed scanner but who occasionally need the platen utility, they must purchase a combination device or two separate scanners (one sheet fed and one platen). Purchasing both types of scanning devices may be cost prohibitive or impossible and, in either case, impractical for applications where portability is desired. For example, service bureaus require the ability to pick up the scanner and host computer, which is attached to the scanner, in order to transport both systems to the jobsite. After the job is finished, the scanner and computer must be brought back to the service bureau headquarters or to the next jobsite. Thus, portability and the ability to reconfigure and perform multiple scanning functions are critical to people who buy scanners to scan documents as a service.
Other limitations of the prior art scanners are the relatively high cost and large size of the form factor associated with the combination production scanners that combine platen and sheet feeding functions in one unit. Since the form factor must be increased, the cost of manufacture is increased over the single function scanning device. Typically, such combination production scanners only come in one of various classes suitable for scanning a single size or style of document. For example, the platen portion of the combination scanner can be equipped to handle 8xc2xdxc3x9711 inch or European sized documents (also known as A4) or they can be equipped to handle 11 by 17 inch documents (also known as A3). Thus, the prior art combination production scanners may not be configured to scan the size of documents that the customer desires have scanned.
As such, a relatively low cost scanning device that can handle various paper sizes in a unit having a relative small footprint, and which combines the functionality of a platen scanner with that of a sheet fed scanner would provide numerous advantages.
The present invention provides a modular scanner with a detachable platen element for either single sheet and/or multiple page scanning which xe2x80x9cdocksxe2x80x9d or attaches to a scanning unit providing sheet fed scanning. With the present invention, the end customer is given the functionality of a platen scanner and the ability to selectively mount or store the platen device. The space associated with the platen element can be saved on the desktop as well as the possibility to purchase the scanner with or without the platen accessory. In addition, the size of the platen element can vary to accommodate various sizes and documents.
Accordingly, disclosed in one embodiment is a scanning subsystem supporting platen and sheet fed scanning of documents. The scanning system comprises a first scanning unit with a first enclosure housing a first set of mechanisms for enabling full sheet fed scanning functions. The first scanning unit also includes a second set of mechanisms for enabling partial platen scanning functions and a docking interface defining an opening in the first enclosure. A second scanning unit with a second enclosure can be attached to the first scanning unit through the docking interface. The second scanning unit includes a third set of mechanisms for enabling complete platen scanning of documents in operable combination with the second set of mechanisms within the first scanning unit.
In one embodiment, the first scanning unit includes a feeder opening through which paper documents can be fed for sheet fed scanning. A first exit opening is provided and adapted to deliver scanned documents from a first location of the first scanning unit. A paper pathway and extends from the feeder opening through the first exit opening. A first image forming subsystem is predisposed within the first scanning unit and configured to scan images appearing on paper documents fed through the feeder opening and transported over the first paper pathway. A feed roller predisposed about the feeder opening facilities the introduction of documents onto the first paper pathway. A separation roller or separation pad can also be employed and used to ensure that only a single sheet of paper is fed through the feeder opening.
The first scanning unit further includes a plurality of rollers predisposed about the first paper pathway for facilitating transmission of paper documents from the feeder opening to either the first exit opening or a second exit opening. The first image forming subsystem can include a lens and a light source predisposed about the paper pathway for directing light onto paper documents entering the first scanning unit through the feeder opening. Mirrors within the first scanning unit are configured for guiding reflected light from the paper document through the lens and onto the CCD. In this way, the first image forming subsystem is able to sheet fed scan a document.
The second set of mechanisms comprise a second image forming subsystem and a drive subsystem for causing said second image forming subsystem to move from a sheet fed scanning position to a pre-platen scanning position. Specifically, motion of the second image forming subsystem along an axis substantially perpendicular to the opening defined by the docking interface is facilitated by the drive subsystem. The drive subsystem can include pulleys and belts which are adapted for engaging the second image forming subsystem and causing its motion along an axis perpendicular to the opening.
In essence, the second image forming subsystem is made to enter the second scanning unit through the opening prior to platen scanning of documents placed on a glass piece attached to the top surface of the second scanning unit. Platen scanning by the second scanning unit occurs as the second image forming subsystem traverses the length of the enclosure of the second scanning unit. In this regard, a Thompson rod can be used to engage a Thompson rod bearing of the second image forming subsystem to guide the motion of the camera and permit it to sweep a document placed on the glass piece during platen scanning. Once the second image forming subsystem traverses the length of the second enclosure associated with the second scanning unit, it can return to an initial pre-scanning position ready for subsequent scanning operations of either the platen scan or sheet fed scanning modality.
According to another embodiment, disclosed is a modular scanner comprising a first enclosure with a stationary camera therein and having a first opening for feeding a document to be scanned, a second opening for delivering a scanned document to a user, and a third opening through which one or more docking mechanisms can join. A first paper pathway extends between the first opening and the second opening within the first enclosure. A document handling means within the first enclosure can receive a document through the first opening and transport it over the first paper pathway to an area within the first enclosure where the stationary camera can scan the document. A light source is predisposed for delivering light energy in the direction of the document with light guiding means adapted for directing reflected light energy from the document to the stationary camera. Also provided is a moveable camera mounted within the first enclosure adjacent to the stationary camera.
The modular scanner can further comprise a second enclosure having a substantially flat top surface with a glass plane thereon and includes an opening at one end adapted for receiving the movable camera when the second enclosure is attached to the first enclosure via the third opening. A first translation means is also provided within the first enclosure for causing the motion of the motion of the moveable camera from a sheet fed scanning mode that places the moveable camera within the opening of the second enclosure. A drive subsystem is also provided within the second enclosure for receiving the moveable camera through the opening and causing the camera to traverse along an axis substantially parallel to the glass plane. Sheet fed and platen scanning of documents are facilitated by the stationary camera and moveable camera, respectively.
Further disclosed is a detachable platen element for a modular scanning system. The platen element includes an enclosure having a top surface with a glass plane attached thereon. The enclosure has one end with an opening for accepting an image-forming subsystem. A translation means is provided within the enclosure and adapted for attachment to the image forming subsystem and causing it to move in a direction permitting scanning of documents placed on the glass plane. The platen element can include a lid with a substantially flat surface suitable for covering documents placed on the glass plane. The lid can be opened and closed with a hinging means that couples the lid to the enclosure. The translation means can include a pulley and belt system adapted to engage the image forming subsystem for facilitating its motion and permitting platen scanning of documents placed on the glass plane. A rod within the enclosure can engage the image forming subsystem and facilitate its movement for platen scanning.